High voltage electric power transmission cables in current use include multiple (e.g., 7) galvanized steel or stainless steel wire strands wrapped with multiple (e.g., 26) aluminum or aluminum alloy wires. A pure aluminum or aluminum alloy wire is often used as a wrapping wire around the steel core, or in some products, aluminum alloy wire may be used without a steel core. Aluminum alloys commonly used in this manner are referred to as 6201 aluminum alloy, 5005 aluminum alloy, or Al-0.3% Zr alloy. Alloy 6201 has a conductivity of (0.31)106 cm−1Ω−1 and a tensile strength of 330 MPa with poor elevated temperature strength retention over time. The strength of 5005 alloy is similar to that of 6201, but its conductivity is (0.32)106 cm−1Ω−1. Al-0.3% Zr wire has conductivity of (0.35)106 cm−1Ω−1, but its tensile strength is lower. An aluminum-Al2O3 composite wire is commercially available as ACCR wire from 3M Corporation and has a conductivity of (0.19)106 cm−1Ω−1 and a tensile strength of 310 MPa with good elevated temperature strength retention over time. The 6201 aluminum alloy wire has a cost disadvantage in that it is about 1.3 times more costly relative to pure aluminum wires. The ACCR wire has a cost disadvantage in that it is about 4.8 times more costly relative to pure aluminum wires. The densities of 6201 and 5005 alloys are similar to that of pure aluminum (2.70 g/cm3); however, ACCR wire has an additional disadvantage in that its density is 3.34 g/cm3, substantially higher than the density of pure aluminum.
There is a need for a new material that can provide high electrical conductivity together with high tensile strength, low density, and strength retention at elevated temperatures at reasonable cost for high voltage electric power transmission and other uses.